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Hidroarilación de las olefinas regioselectiva catalítica (alqueilación) por transferencia secuencial de
Chen-Fei Liu1, Xiaohua Luo1,2, Hongyu Wang1
1Department of Chemistry, National University of Singapore, 4 Science Drive 2, Singapore, 117544, Republic of Singapore.
Journal of the American Chemical Society
|June 21, 2021
Resumen
Este estudio introduce un nuevo método catalítico para la hidroarilación y alquenilización de las olefinas, creando estructuras ramificadas complejas. La nueva reacción catalizada por níquel ofrece una ruta altamente selectiva y eficiente a valiosos compuestos químicos.
Área de la Ciencia:
- Química orgánica
- Catálisis
- Metodología sintética
Sus antecedentes:
- La funcionalización de hidrocarburos de alqueno es crucial en la síntesis orgánica.
- Las reacciones selectivas ramificadas con olefinas no activadas son un desafío.
- Los métodos duales catalíticos existentes a menudo implican la transferencia de átomos de hidrógeno metálico (MHAT).
Objetivo del estudio:
- Desarrollar un nuevo sistema catalítico para la hidroarilación/alqueinilación selectiva de Markovnikov de olefinas no activadas y activadas.
- Para lograr altos rendimientos y regioselectividad en la formación de centros terciarios y cuaternarios sustituidos por arilo y alqueno.
- Para aclarar el mecanismo de reacción, distinguiéndolo de las vías anteriores dependientes de MHAT.
Principales métodos:
- Utilizando un complejo dimérico de Ni (I) como catalizador.
- Utilizando una base de alcóxido exógeno como fuente de hidrógeno.
- Bromuros orgánicos o triflados (de fenoles y cetonas) que reaccionan con las olefinas
Principales resultados:
- Se ha logrado la hidroarilación/alqueinización selectiva de Markovnikov de varias olefinas.
- Productos aislados con centros terciarios y cuaternarios sustituidos por arilo y alqueno con un rendimiento de hasta el 95%.
- Se obtiene una excelente regioselectividad, con proporciones superiores a 99:1.
- Los estudios mecanicistas indicaron una vía no radical que involucra carbonicelación seguida de transferencia de hidrógeno.
Conclusiones:
- Se ha establecido un nuevo protocolo de catalizador único, eficiente y altamente selectivo para la funcionalización de hidrocarburos de alqueno.
- El método evita la transferencia de átomos de hidrógeno metálico, procediendo a través de un mecanismo no radical distinto.
- El protocolo demuestra su utilidad en la síntesis de andamios médicamente relevantes.
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